That is a loaded question. I am writing a book on it and teach a class in it once a year. I think that if you refer to "Glassnotes" you will find rudimentary coloring stuff. There are also tons of things in these archives that I have written from time to time and you should start there. Dave is also right that Scholes has some good basics as does "A textbook of Glass Technology" by Hodkin and Cousen from back around 1915. I may give a very short course at the conference, and I may not since I anticipate being a little harried.

And this is not meant to put you off, I just don't like glossing over stuff so I don't want to write a treatise right now. I will however sell you one when I finish it.

Definately post when you are finished with your book Pete, I'd be interested in one. As to your class I'm thinking it will be out of my league right now, but maybe in a year or two I'll make it to one.

[ I use SP87 for a clear when I am working it with colored glasses. I would not use it as a stand alone clear and would make either the formula Dave has listed that I wrote almost thirty years back, or a very nice 11% lead glass I pull out for special occasions. The glass should be appropriate to the project.

Just remember, get a good scale, a very good scale. I have two and I cross check every time. [/b][/quote]

Thank's Pete, Food for thought. I like the lead crystal myself. I know some of these guys probably have never had the pleasure of working a good lead glass. I'm in the process of aquiring about a ton of cullet from my employer. "They give it away". Do you believe it? I'll use it for those special projects that come up occasionaly.

.
I find it very exciting to have this level of freedom in having control and adjustability on what I'm using. Particularly having a "one fits all" for becoming oxidising or reducing batch on one mix.

I know, It's a power rush when you think you are in total control of your passion. Being able to change things at will to sute your needs is a great feeling. I envy Pete and his operation down yonder. Also sounds like you have a handle on it pretty well. I need to do some studying to aquire the knowlege for this kinda thing. Right now I'm cramming so much info into my brain I'm getting headaches from it. Or so my Dr. says.

Enviro issues, reasonable and unreasonable, are a big burden on small businesses these days. You might have some bureaucrat hit you with some serious fines and penalties for having that stuff. Just plain old glass dust is a very hot item among the enviro enforcers at the moment. They would probably get very excited about the lead content. Particularly since you hauled it in there and it's not some leftover from the past.

I was in the scrap metal business for many years and finally had to give it up. I ran a very clean operation but enviro enforcement and declining prices finally tilted the risk to reward factors too far in the wrong direction.

I would hate to see you take a big hit right in the beginning.

It may seem like a fairly minor point at the moment, but the low toxicity of this particular batch could become quite important in the future.

I read you loud and clear Dave. I have checked on it and there are no restrictions on cullet lead or no lead. I had my melting dept check on it. Besides most of the lead is burned out of the cullet. When we remelt it in the tank we have to add the lead oxcide just as if we were adding clear batch. Our cullet ratio is 69% right now. I will do a test melt and if I see the tell tail yellow orange color of lead I'll blow some stemware and dump the rest and refill with a new batch or cullet melt. I really don't think I'll have any problem with it though. My biggest worry is the effects it could have on my elements.

Well, I'm back from Oaxaca and Magic mountain is back! Jay, The lead is not "burned out" of the cullet and I don't care who told you that. The lead is a physical part of the glass and that particular glass could not exist without the lead content it has.
The risk is the cullet is mostly in the fine dusts that inherently exist in the cullet itself. For years we all used to say that the lead is bound up in the cullet and it is perfectly safe. It isn't -and that is why Lead glasses can no longer be used for decanters..

I think your headaches are a reasonable concern and I doubt that you need to add any more crap to the stew you are already ingesting. I would not say "Don't take the cullet" but I would say that it is not benign stuff. It has about 36 percent lead in it. You also are going to find that it is an absolute bitch to melt without cords. Those stirring rods really are good for something.

Well, I'm on my 5th pot of this stuff and I'm still just thrilled. I'm charging and melting at 2200F, working at 2050. It will squeeze in about 4-5 hours at 1900 or 2000. It will reboil if I go above the valence change on the antimony around 2100F.

Updates...

It anneals (for me) around 920-40F top ed of the anneal range ...your mileage, thermocouple, annealer, phase of the moon, or quantity of chicken blood sprinkled with incantations or arrangement of idols may vary. Of course both annealers are 10 degrees different in what they want, and that's going by the ol' slumped cane test.

I really should have done the slump test first, I turned a days worth of furnace bead cane into something Salvador Dali would have been proud of.

I get an occasional white silica snot (literally just one or two tiny ones) on the top of the melt clinging to the pot wall occasionally. No big deal, pick 'em out and continue on. I'll also get maybe one or two silica (clear) stones in some, not all melts. Also not a major issue for what I'm doing. Long cooking does not seem to change either of these so I'm thinking I may have some not-quite-enough mixing issues, or of course, higher cook/charge temp would probably help but that's not a recommended option with the wire melter.

I don't know why this is... but my nasty 'ol pot has quit throwing iron into the glass and it's coming out beautiful and clear.

I'm SO happy with this glass!!!!!

Pete,

I definitely heard you on your warnings about changing COE with the silica and not messing with the soda/potash ratio, and about how this formula is not kind to changes...but....two of the modifications I'll eventually want to try are bumping this stuff up in COE to go along with Moretti and getting a good manganese purple, which, I suspect, should require much more potassium to eliminate the brown tint.

If I try these two things what sort of trouble should I be watching for? Cords?

When I try for the Moretti match would it be wise to keep the soda and potash at the same ratio to each other as the original and up the quantities or would more of either the soda or potash be a safer way to go?
I don't mind the cost of using more potash if it will make nicer glass.

A little research turns up a recommendation for substituting 13 parts potassium carbonate for 10 parts sodiuim carbonate for equal alkaline effect. Does this match your experience?

I think you could run your potash up two lbs without messing it up and probably the soda by one lb. That will move the expansion a lot. I don't like to see the modifier falling below 8% but it is still tolerable. The silica content is still comfortably high.That glass makes a very nice manganese purple already. It also will do incredible things with selenium. A beautiful peach glass.

I have never messed with those substitution formulas. They pop up in the Manheim book but I have not had the luxury of those experiments. They are a little vague. I will try them out in the spreadsheet during the class in January.

[quote]Originally posted by Pete VanderLaan
[b]Well, I'm back from Oaxaca and Magic mountain is back! Jay, The lead is not "burned out" of the cullet and I don't care who told you that. The lead is a physical part of the glass and that particular glass could not exist without the lead content it has.
The risk is the cullet is mostly in the fine dusts that inherently exist in the cullet itself. For years we all used to say that the lead is bound up in the cullet and it is perfectly safe. It isn't -and that is why Lead glasses can no longer be used for decanters..

I hear ya Pete. We take it for granted that the tell tail yellow orange on the top of our gloryholes is from the lead "burning out" of the glass. This color is all over the blowing room specially at the tank area. But, the company has the blowing room air tested for lead and they still say that it's below alouable standards. The headaches persist and I'm not the only one getting them now. The Drs. are stumped. Now they say it's cluster headaches and they will one day cease. I know about the decanters. I made the decanters for Steuben. I really liked making em too. I have a couple but don't keep liquids in them just for that reason.

The yellow flame showing the lead being present doesn't mean that it is burning out, only that it is present. If you had strontium in the glass it would show a red tone.

Don't let the doc's be "stumped " Jay. I think if the problem is getting around to other workers, it is a union issue and possibly one for OSHA although I would hold that card a while. Headaches are very real and almost always are the result of something being not right. Pursue it thru the union, not personally. Don't become a target.
Reading your list of illnesses is like reading the munchhausen syndrome, but it's real.

Even so, the lead is always there and often takes a dusting form, particularly in a cullet. It's dangerous. While it can't be absorbed thru the skin, it can be breathed.

jay, could you all be getting carbonmonoxide poisoning? that would not show up on chem tests. i would spring for some independant testing though. conspiracy theorys and all being believable to me. good luck, rosanna

I noticed today that there was a foul rotten egg smell floating around my gaffers bench. The caffiteria is just down the hall and usually there is a smell of bagels and such but this morning there was no food smell and I started looking for the GAS LEAK. It was in my torch. On the inside of the control box. One of my assistants said he smelled it last week but forgot to bring it to my attention. I went and got the safety lady and she had it fixed right away. I still got the headache but we will see if it subsides now. If not I will get tested for heavy metals up in Rochester or Buffalo. Corning controls the medical people in and around Corning. We did have a high lead situation back in 1990 and we wern't aloud to work without recals on. Try to blow glass while wearing a face mask and helmet. It's an experiance I tell ya.

[quote]Originally posted by Pete VanderLaan
[b]The yellow flame showing the lead being present doesn't mean that it is burning out, only that it is present. If you had strontium in the glass it would show a red tone.

It's not the flame that is yellow Pete. There is actually a yellow orangeish red dust or deposit on the gloryhole just above the doors. It was worse when we had the old gloryholes. It's also all over the tank area but our air sampling says alls ok. Very low airborne lead particals. Well under the legal limit. Could this deposit be from running the burner in a reduction state? Flame coming out the door.

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